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authorEric W. Biederman <ebiederm@xmission.com>2009-04-03 00:36:27 -0700
committerEric W. Biederman <ebiederm@xmission.com>2009-11-06 03:52:55 -0800
commitda3f6f9b3e0d1e73975ca81ae124406bf1587d40 (patch)
treeab2e5bb6366b0bdc00ec1bc5c02e610c1c77195d /kernel/sysctl_binary.c
parent2830b68361a9f58354ad043c6d85043ea917f907 (diff)
downloadlinux-2.6.34-ux500-da3f6f9b3e0d1e73975ca81ae124406bf1587d40.tar.gz
sysctl: Introduce a generic compat sysctl sysctl
This uses compat_alloc_userspace to remove the various hacks to allow do_sysctl to write to throuh oldlenp. The rest of our mature compat syscall helper facitilies are used as well to ensure we have a nice clean maintainable compat syscall that can be used on all architectures. The motiviation for a generic compat sysctl (besides the obvious hack removal) is to reduce the number of compat sysctl defintions out there so I can refactor the binary sysctl implementation. ppc already used the name compat_sys_sysctl so I remove the ppcs version here. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'kernel/sysctl_binary.c')
-rw-r--r--kernel/sysctl_binary.c50
1 files changed, 50 insertions, 0 deletions
diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index 930a31cd708..775cc49da62 100644
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -176,3 +176,53 @@ SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)
return error;
}
+
+#ifdef CONFIG_COMPAT
+#include <asm/compat.h>
+
+struct compat_sysctl_args {
+ compat_uptr_t name;
+ int nlen;
+ compat_uptr_t oldval;
+ compat_uptr_t oldlenp;
+ compat_uptr_t newval;
+ compat_size_t newlen;
+ compat_ulong_t __unused[4];
+};
+
+asmlinkage long compat_sys_sysctl(struct compat_sysctl_args __user *args)
+{
+ struct compat_sysctl_args tmp;
+ compat_size_t __user *compat_oldlenp;
+ size_t __user *oldlenp = NULL;
+ size_t oldlen = 0;
+ ssize_t result;
+
+ if (copy_from_user(&tmp, args, sizeof(tmp)))
+ return -EFAULT;
+
+ compat_oldlenp = compat_ptr(tmp.oldlenp);
+ if (compat_oldlenp) {
+ oldlenp = compat_alloc_user_space(sizeof(*compat_oldlenp));
+
+ if (get_user(oldlen, compat_oldlenp) ||
+ put_user(oldlen, oldlenp))
+ return -EFAULT;
+ }
+
+ lock_kernel();
+ result = do_sysctl(compat_ptr(tmp.name), tmp.nlen,
+ compat_ptr(tmp.oldval), oldlenp,
+ compat_ptr(tmp.newval), tmp.newlen);
+ unlock_kernel();
+
+ if (oldlenp && !result) {
+ if (get_user(oldlen, oldlenp) ||
+ put_user(oldlen, compat_oldlenp))
+ return -EFAULT;
+ }
+
+ return result;
+}
+
+#endif /* CONFIG_COMPAT */